I like the "why feet" or "ewww feet" responses the best... you will get them a lot.
It kinda makes you wanna tell them to go ask general surgeons "why bowel," OB guys "why vagina," derm guys "why acne," and psychiatrists "why perverts and sociopaths?" There's not a specialty I can think of that doesn't have aspects which are offuputting to the lay person.
I usually just reply that docs of any specialty need to know and understand and be comfortable with the whole body.
The bottom line is that pod is a great specialty if it interests you, and it really is a great time to enter the field with the advanced PMS residency training models in place now. You get to do some surgery, you get to do clinic and know patients for a long time, and you help many people almost immediately. If you're good, you will get the respect (and referrals/consults) of many other specialists as part of the health care team. However, if you're the kind of person whose ego can't take being "just a podiatrist," then it's really not for you. You might laugh, but it's not a joke... just look at the multi-page "MD is better than DO" threads that go on and on in the other forums.
Perhaps even more important than any of that BS ego stuff, if Medicare and the US healthcare system in general goes belly-up during our practicing career (as predicted), podiatry still offers plenty of services which people need and will pay cash for. Nobody can walk around with a painful bunion, ingrown toenail, plantar fasciitis, foot ulcer, etc, but those are reasonably cheap fixes that pods can generally take care of in the office or at least an outpatient basis. Barely anyone's gonna be able or want to pay out of pocket for a MRI and reading, a Whipple procedure, Invanz, or a hip replacement... but podiatry has a lot of services that are reasonably priced and can provide a fairly quick fix. It will always have an important role and be a good source of income IMO...